Of course it's taxable - if you give someone $20 for their project and get a t-shirt in return, then that is taxable just as any other deal, and even if there is no profit/taxable net income, then VAT applies for the transaction.

If crowdfunding was like purchase of shares (which it isn't), then it wouldn't be taxable initially, but would have a capital gains tax when you sell those shares.

Most of the crowdfunding projects are in essence similar to preorders, and thus would be taxable as any other sales - if there are true donation projects, then they'd need to file for nonprofit status to be able to get tax-exempt donations.